1. Field of the Invention
The subject invention relates to the withdrawal and monitoring of fluids from the body of a patient or user. More particularly, the subject invention is directed to a portable system for non-invasively withdrawing bodily fluids from the skin of a patient or user. Further, the subject invention is directed to the monitoring of the fluid non-invasively withdrawn from the skin. Even further, the subject invention directs itself to sensing a constituent in the extracted fluid and to the analysis of said constituent to determine a quantitative characteristic thereof.
The subject invention is further directed to the non-invasive withdrawal of a bodily fluid from the skin of a user or a patient by applying to the user's skin a predetermined combination of negative pressure and ultrasonic energy. Even further, the subject invention is directed to the non-invasive withdrawal and monitoring of bodily fluid from the skin of a user by applying to the user's skin a predetermined combination of negative pressure and an electric field, where the electric field applied to said skin induces electrical currents on the skin. Alternatively, the non-invasive withdrawal of bodily fluid from the skin is further effected by applying a predetermined combination of negative pressure, ultrasonic energy, and an electric field to the skin of the user.
2. Prior Art
Prior art non-invasive techniques for delivering substances to a patient's skin include sonophoresis (application of ultrasound energy to the skin to enhance substance delivery to the skin) and iontophoresis (the application of electric fields to the skin to induce currents therein to facilitate substance delivery to the skin). Also known in the prior art is the technique of sonophoretic extraction of bodily fluids from the skin, as is described in U.S. Pat. No. 5,617,851, by Lipkovker.
In addition to these prior art systems, other relevant prior art is directed to apparatuses and methods for monitoring substances or constituents of interest present in bodily fluids, including the determination of glucose concentrations in such bodily fluids.
However, the prior art fails to teach or suggest a system for non-invasively withdrawing or extracting fluid from the skin of a patient or user in accordance with the teachings of the subject invention. It follows that the prior art fails to teach or suggest a system that provides the particular methodology of the subject invention for both non-invasively withdrawing and monitoring fluids from the skin of a user.